Re: [PATCH qemu 06/13] target/riscv: rvv: Add tail agnostic for vector integer shift instructions

[Weiwei Li]

在 2022/3/7 下午5:38, ~eopxd 写道:
> From: eopXD <eop.chen@sifive.com>
>
> Signed-off-by: eop Chen <eop.chen@sifive.com>
> Reviewed-by: Frank Chang <frank.chang@sifive.com>
> ---
>   target/riscv/insn_trans/trans_rvv.c.inc |  1 +
>   target/riscv/vector_helper.c            | 12 ++++++++++++
>   2 files changed, 13 insertions(+)
>
> diff --git a/target/riscv/insn_trans/trans_rvv.c.inc 
> b/target/riscv/insn_trans/trans_rvv.c.inc
> index ac6379a8fc..f1838fbf11 100644
> --- a/target/riscv/insn_trans/trans_rvv.c.inc
> +++ b/target/riscv/insn_trans/trans_rvv.c.inc
> @@ -1871,6 +1871,7 @@ static bool trans_##NAME(DisasContext *s, arg_rmrr *a)    
>          \
>                                                                      \
>           data = FIELD_DP32(data, VDATA, VM, a->vm);                 \
>           data = FIELD_DP32(data, VDATA, LMUL, s->lmul);             \
> +        data = FIELD_DP32(data, VDATA, VTA, s->vta);               \
>           tcg_gen_gvec_4_ptr(vreg_ofs(s, a->rd), vreg_ofs(s, 0),     \
>                              vreg_ofs(s, a->rs1),                    \
>                              vreg_ofs(s, a->rs2), cpu_env,           \
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> index 56a32adcb9..6d79908ffe 100644
> --- a/target/riscv/vector_helper.c
> +++ b/target/riscv/vector_helper.c
> @@ -1216,6 +1216,9 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1,          
>                 \
>   {                                                                         \
>       uint32_t vm = vext_vm(desc);                                          \
>       uint32_t vl = env->vl;                                                \
> +    uint32_t esz = sizeof(TS1);                                           \
> +    uint32_t vlmax = vext_get_vlmax(env_archcpu(env), env->vtype);        \
> +    uint32_t vta = vext_vta(desc);                                        \
>       uint32_t i;                                                           \
>                                                                             \
>       for (i = env->vstart; i < vl; i++) {                                  \
> @@ -1227,6 +1230,8 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1,          
>                 \
>           *((TS1 *)vd + HS1(i)) = OP(s2, s1 & MASK);                        \
>       }                                                                     \
>       env->vstart = 0;                                                      \
> +    /* set tail elements to 1s */                                         \
> +    vext_set_elems_1s_fns[ctzl(esz)](vd, vta, vl, vl * esz, vlmax * esz); \
>   }
>   

Use vlmax here and in the previous patches may not contains all the tail 
elements:

"When LMUL < 1, the tail includes the elements past VLMAX that are held 
in the same vector register"

Regards,

Weiwei Li